The present invention relates to a draining structure for a diving mask, and more particularly to a draining structure for a diving mask that is able to drain off water accumulated in the diving mask via two side outlets at a rear end of the diving mask, to prevent water from sideward flushing open a valve leaf and entering the diving mask, and to protect the side outlets from deformation when the diving mask is put on a diver""s head.
A diving mask typically includes a rigid skirt framing a lens, and a soft head cover fixedly connected to the rigid skirt for putting on a diver""s head. Since the head cover does not always fit with the diver""s head contour, there are frequently clearances left between the diving mask and the diver""s face, resulting in invasion of water into the diving mask to interfere with the diver""s face or even seriously affecting the diver""s breath and vision. It is therefore necessary to timely drain off water accumulated in the diving mask.
A common way to drain off water accumulated in the diving mask is to mount a valve leaf to a bottom of a forward projected nose portion of the diving mask, so as to provide a draining valve for the diving mask. The draining valve is a one-way valve that allows the valve leaf to open only in an outward direction, so that water accumulated in the diving mask could be drained off via the valve leaf while external water is prevented from entering the diving mask via the valve leaf. The diver needs only to expire via nose to blow the accumulated water out of the diving mask via the outward openable valve leaf.
Gas expired by the diver produces air bubbles in the drained water. Since the draining valve is provided below the nose portion at a central bottom of the diving mask, the air bubbles in the drained water tend to move upward in front of the diving mask and seriously interfere with the diver""s vision.
To overcome this problem, there is developed a draining structure provided at the bottom of the nose portion of the diving mask to guide the air bubbles produced by the diver""s expiration to two lateral sides of the diving mask, so that they do not interfere with the diver""s vision.
FIGS. 1 to 4 shows a conventional diving mask and associated draining structure disclosed in U.S. Pat. No. 5,860,168. Wherein, FIG. 1 is a sectioned side view of the conventional diving mask, FIG. 2 is a partially sectioned front view thereof, FIG. 3 is a side view of the conventional diving mask before being worn by a diver, and FIG. 4 is a fragmentary side view of the same diving mask after being worn by a diver.
As shown in FIGS. 1 to 4, the conventional diving mask, which is generally denoted by letter A, includes a rigid skirt 1 framing a lens 11, and a soft head cover 2 fixedly connected to the rigid skirt 1. The soft head cover 2 includes a forward projected nose portion 21. A valve seat 24 having a through hole 23 is mounted on a bottom 22 of the nose portion 21. A valve leaf 25 is mounted on the valve seat 24 to locate below the through hole 23. The valve leaf 25 can be opened in an outward direction only, and normally closes the through hole 23 to prevent external water from invading the diving mask A via the through hole 23. When a diver wearing the diving mask A expires via his or her nose, the valve leaf 25 is blown outward to open the through hole 23, allowing any water accumulated in the diving mask A to be drained off.
A curved draining guide 26 downward extends from a lower front end of the nose portion 21 by a predetermined distance and then turns rearward to extend toward two sides of the soft head cover 2, such that a water passage 27 is formed between the bottom 22 of the nose portion 21 and the draining guide 26 to extend rearward and sideward. When the diver expires to drain off the accumulated water, air bubbles produced in the drained water by the diver""s expiration are guided through the water passage 27 to two sides of the diving mask to avoid interfering with the diver""s vision in front of the diving mask.
Following drawbacks are found in the above-described conventional diving mask A:
1. As shown in FIG. 1, the curved draining guide 26 is located below the valve leaf 25 such that a wide transverse opening 28 is formed between the draining guide 26 and a rear end of the bottom 22 of the nose portion 21. When a diver wearing the conventional diving mask A jumps into water in a vertical position, an instantaneous high water pressure produced at the instant of contact of the diving mask A with water surface will flow into the water passage 27 via the wide transverse opening 28 to impact on one side of the valve leaf 25 to open the valve leaf 25 and accordingly the through hole 23, allowing external water to instantaneously invade the diving mask A, as indicated by the arrow xe2x80x9caxe2x80x9d in FIG. 1, and accumulate in the diving mask A.
2. Since the water instantaneously accumulated in the diving mask A must be quickly drained to avoid any adverse influence on the diver""s normal breath, the diver has to expire as soon as he or she starts diving. This is, of course, very inconvenient to the diver.
3. As shown in FIG. 2, the conventional diving mask A is designed to guide air bubbles produced in the drained water by the diver""s expiration to two lateral sides of the diving mask via the water passage 27, as indicated by arrows xe2x80x9cbxe2x80x9d in FIG. 2. However, a part of the air bubbles would pass the wide transverse opening 28 between the rear ends of the bottom 22 of the nose portion and the draining guide 26 to move through the bottom to the front of the diving mask A, as indicated by the arrow xe2x80x9ccxe2x80x9d in FIG. 1, and interfere with the diver""s vision.
4. As shown in FIG. 3, there is a proper space left between two side outlets 29 of the water passage 27 and two lateral edges of the soft head cover 2 when the diving mask A is not worn by a diver. The side outlets 29 of the water passage 27 are, however, deformed and narrowed when the soft head cover 2 is put on the diver""s head and stretched out wardly to compress against the side outlets 29, preventing the air bubbles from smoothly moving out of the water passage 27 via the side outlets 29. This would cause more air bubbles to move toward and release from the wide transverse opening 28, and finally move through the bottom to the front of the diving mask A, as indicated by the arrow xe2x80x9ccxe2x80x9d in FIG. 1, and seriously interfere with the diver""s vision.
It is therefore a primary object of the present invention to provide an improved draining structure for diving masks to eliminate the drawbacks existing in the conventional structure by guiding the air bubbles produced by the diver""s expiration to two lateral sides of the diving mask, preventing the valve leaf from being sideward opened, and protecting the water passage against deformation when the soft head cover is put on the diver""s head.
To achieve the above and other objects, the diving mask of the present invention includes a rigid skirt framing a lens, and a soft head cover fixedly connected to the rigid skirt. The soft head cover includes a forward projected nose portion. A valve seat having a through hole is mounted on a bottom of the nose portion. A valve leaf is mounted on the valve seat below the through hole. The valve leaf can be opened in an outward direction only. The valve leaf normally closes the through hole to prevent external water from invading the diving mask via the through hole. When a diver wearing the diving mask expires via his or her nose, the valve leaf is blown outward to open the through hole, allowing any water accumulated in the diving mask to be drained off.
A curved draining guide extending downward from a lower front end of the nose portion by a predetermined distance and then turns rearward to extend toward two sides of the soft head cover, such that a water passage is formed between the bottom of the nose portion and the draining guide to extend rearward and sideward.
The draining guide of the present invention is characterized by a hole located directly below the valve leaf. When a diver wearing the diving mask of the present invention jumps into water in a vertical position, an instantaneous water pressure produced at the instant of contact of the diving mask with water surface will fully act on a bottom side of the valve leaf via the hole on the draining guide to therefore further push the valve leaf upward to tightly close the through hole on the valve seat without the problem of sideward opening of the valve leaf.
The draining guide of the present invention is also characterized by an upward projected transverse flange provided along a rear end of the water passage to reduce a vertical openness of a transverse opening at a rear end of the water passage and to intercept air bubbles produced by the diver""s expiration at the transverse opening, lest the air bubbles should move through the bottom to the front of the diving mask to interfere with the diver""s vision.
The flange provided along the rear end of the water passage also reinforces the water passage at the transverse opening, so that the two side outlets of the water passage have increased compression strength and are not deformed and narrowed by the head cover when the latter is put on the diver""s head and outward stretched to press against the side outlets, allowing the air bubbles to smoothly and quickly move out of the diving mask via the side outlets.